A. Field
The present invention relates to a zero-resetting device for a timepiece and more particularly for a chronograph.
B. Related Art
In conventional chronographs, zero resetting of the hands of the seconds, minutes, and hours counters is brought about through a push-button which, when actuated, sets in motion a monoblock part comprising hammers striking heart-shaped zero-resetting cams mounted on the arbors of the hands.
These zero-resetting devices have several disadvantages. Notably, they are relatively bulky, inasmuch as the excursion of the monoblock part must be sufficiently large for the hammers to be out of the way of the cams when at rest, but pressing against the cams during the zero-resetting operation. Owing to manufacturing tolerances, moreover, the zero resetting of the minutes and/or hours hands generally lacks precision, since the hammers are unable to strike the three cams in a perfectly exact fashion. Finally, the hammers exert a pressure on the zero-resetting cams that can be very high, possibly damaging or even breaking the arbors of the hands.